Resilient coupling for grinding tools



Jan. 19, 1954 w. J. HIGERT RESILIENT COUPLING FOR GRINDING TOOLS Filed July 2, 1952 /7 O A??? INVENTOR.- l4 /////0m J H/ger'f Patented Jan. 19, 1954 se BESILIEN T GQUBLING EOR GRINDING J srt San fian ee: 9e?- Annlication July 2, 1 52,.-Serial .No- 236,834

T 1 2 st s i'es ieeeiel s se e zal t ifi i ii i @QES $5: S w'h'r'i'fi the coupling is atlggg gl 7 of a rotary vdrive.511'f it to a otary gr i @2 2 .teil qiiteqti etweenthe abrasiiz material and the work and enabling the use of lower ptal ns speeds; vand, atshieziine. thetransmissmn of bration an shooh te reducing :operat fatigue Another ,QbJe t ,of heimesent invention .to provide a 7 vecgupljn g 1 iithe character described, which is vvn1pesed 401' a'sminimum number of sturdily f ormedsnarts, designeditor leas'y assembly into a unit vpossessing high strength .andWear hanacteristiessand.sbeing of minimum size n and weight for qpmenientlimanual"support andlmanipulation.

The invention rpossesseshther objects and features ofuadvantage, somelo'f which; with the raregoing, swilh bemsetetortli imthe following descriptions hf..the prei.'erred form of the invention whi'eh is illustrated instherdrawmg'accompanying and forming part .of the" specification? It is to be understood, howeventhat ivaviationsin the showingsmade by the said draw-ing and description may he adaptediwiithin the stone 'of the' invention aslsetforthinthe claims.

Referring to "said erasing;

Figure is across-sectional view of a coupling constructed in accordance-"with the p'i'els'eiiti' iiivention taken fi-iongeits longitudinal" axis and showing the coupling-.inlconnected positionto a hand ,drill motor ,and -aijgriinding .stohefthe cou-K aimseneratin load.-

es eseet enal n w; or." thedcouen-figure rebut shown in a n no-load condition.

. 0116131101, thereby v v of lsofterrub .iflli? emejerindera .V....l m.en J-I P f teflsq lsllls are termed with eones -t .1 and. mymme ricaltothe qom- 9 me n and J14, and mounted Joeaqe sirsi inadt of resilient. distort- 9 i M -tel shel n pposite sid s .3; ,.a nd Q23 @lemnesi same 19 .-.by means of e HE IQHQQ i ,Qai i ili a propriately se ured to tllgs l llsil en Zso as to permit relatiye dis- Qlil ms i sbemeenithe sgQtions. ,As an importel lee-tyre Q the pres nt invention,- the seciQ L .J I, .1? .QfiS p 2, .coonerate to "define a hel kb l .fQI' 1 1? pad 3 31f .s mewhat'zlarger vglg nre tlgan the padsoas to prpyide a clearance betwe n themed a d the surrQundingparts-mto hich he adimay the resiliently distorted" when UA Q I .mmditions. {,QI iuntherimpontance is iQnQ s ch clearance andthe size and resis ance o distortion ,Qf .the .pad, 0 that the amo nt of th learaneewili limitith distortion dis iller-paid and lthierebytl-imit the extent of relatehisnlacement permitt d .the'seotions.

To efieqfilate the .above'operation, the pad is nrei ra ly instructed er amaterial having-a fi lfie pf softnessand resistance .to distortion fbut fii l si nhstantially .inonmpriessible'. lItubb tamin flmzreeeof. hardness is quite suitable for this gnurpose, aswelLaSyarious synthetic rubbers. Theddegree of hardne'ss or elasticity of'the material isindt critical and may be selected -o.ver a relatively Wide range for "best adaptation to various .Q0nditions 'met in grindingoperations. Likewise. thepinitialeompression or preloadilng bf th.e.p,ad.;is ,not critical, itsbein'g sufficientlthat the nad lge' .nlai ediftrmlynnderssunh a preload so as 9 sand ifi lnly sur e .;the sections into Hi silliistrate inihedrawings;

. na t e tof ruh eerno Q alatiherenee ee ii "secure then? C w by'fxneahs of "suitable cem nts by v'uie'aniziifg the riihlieri'iad'dirtlvto the'faees: @eInsthe c'oi'lstrution abate described; the couplifig Zproizide's 1a .resilientrush ion ldetiilfi"tfie drive shaft and the grinder attachment wherein limited resilient, torsional, axial and angular displacement is permitted between the sections up to the automatic stop provided by the filling of the aforementioned clearance by the distortion of the pad. The type and character of resilient displacement between the sections provided in the present coupling affords the many advantages in use hereinabove noted. In grinding, waste and grit from the stone and from the surface being ground, builds up between the stone and the surface. Where the grinding stone is rigidly connected to the drive shaft, grinding operations must be frequently halted, in order to remove the accumulation of this waste and grit, as otherwise it will cause a scoring and premature breaking of the stone and gouging of the work. With the use of the present coupling, the grinding stone may move momentarily away from the work, as the waste and grit builds up, so as to free itself and the work from any such accumulation of waste and grit. In this manner the stone will be constantly self-cleaning and thereby prevent scoring or breaking of the stone and damage to the work as well as constantly bringing fresh, sharp grit portions into grinding engagement with the work. Some of the results from the foregoing are, as above noted, improved precision and nnish of the work; longer stone life with less frequent dressing of the stone; substantially increased speed and efficiency of grinding operations, and permitting lower grinding speeds and cushioning the normal vibration present in the grinding operations and thereby lessening operator fatigue. The co-action of the parts also permits the bringing of much larger abrasive areas into contact with the work and a much heavier loading of the grinding attachment than where a solid or rigid connection is used. In this connection it will be noted that the use of the resilient distortion of the pad as an automatic stop or limit to relative displacement between the sections provides a resistance to such displacement which increases as the stop is approached. Hence the greater the loading of the tool, the greater the effort of the pad to cause a freeing up of the accumulation of waste and grit in the grinding zone, making it virtually impossible to contain any substantial accumulation of such material in the grinding zone where damage to the stone and the work may occur.

In the form of the device illustrated in the accompanying drawing, the sections II and l2 are of disk shape, having enlarged center hub portions 26 and 21 formed with. axial threaded bores providing the fastening means l3 and I4 above referred to. As here shown, the drive shaft I6 is provided with a threaded end portion 28, which may be inserted into the bore l3, and a shoulder or collar 29- engageable with the end of the hub 26 for limiting such insertion and securing the section I I and shaft l6 for joint rotation. Similarly, the grinding stone ll here illustrated is provided with a centrally arranged, threaded sleeve 3|, engaged with a threaded adapter .32 also threaded into the bore M, the stone and section l2 being spacedapart by a collar or flange 33 on the adapter, through which rotational force is transmitted from the section to the stone. sections surrounding the hubsmay be of flat, disk-like form, as illustrated, and of a thickness consistent with the required strength. The confronting faces l8 and 19 of the sections may be flat, as illustrated, although other forms symmetrical to the axis of rotation and suitable for The interlocked engagement with the opposite sides 22 and 23 of the pad may be used.

The casing 24 is here of tubular form having an inturned flange 34 formed at one end for retaining within the casing a peripheral shoulder 36 formed on the section l2 and, as will be noted from the drawing and of importance in the operation of the device, the section 12 and its shoulder 36 are of smaller diameter than the casing 24 and its flange 34, soas to provide a sufficient clearance therebetween to permit a tilting of the section 12 within the casing as well as a free axial and rotational displacement of the section in the casing. As a further feature of the present construction, the opposite end of the casing 24 is formed with a reduced section 31, which is crimped or swaged over the periphery of section I i so as to secure the pad 2| and section i l firmly within the casing with a desired amount of initial compression of the pad. This type of assembly has several advantages in effecting reduction in waste, assuring concentricity of parts and dynamic balance and a precise preloading of the pad in a desired amount. The aforementioned clearance for the pad is here provided in part by forming the pad with a circular periphery 38 of somewhat smaller diameter than the internal diameter of the casing so as to provide an annular space 39 therebetween, in which the pad may distort while resiliently resisting relative displacement of the sections II and I2, including torsional displacement due to loading, axial displacement caused by forcing the stone l1 against the work, and angular displacement of the axis of the stone and drive shaft, as may be caused by shifting of the manual support for the hand-held drill motor 4|,here shown for driving the shaft 56. As will be understood, the initial and subsequent compression of the pad provides an automatic self-restoring and self -aligning action of the sections functioning always to bring the sections it and 12 into their original axially aligned positions.

While the pad 2| may be of solid disk-shaped form, greater resilient action of the character described may be obtained by forming the pad in the shape of an annulus with a concentrically arranged hollow core defined by an internal wall 4'2, which cooperates with internally spaced, concentric, cylindrical bosses 43 and M extending axially from the opposite faces i8 and IQ of the sections to provide a second clearance space 46. As may be seen from the'drawing, the bosses 43 and 44 are preferably of an equal diameter somewhat less than the internal diameter of wall 42, so as to provide the annular space 46 therebetween, into which the i'nternalportion of the pad may distort, while "resiliently resisting relative displacement of the sections.

The clearances 39 and 46 between thepad and the casing and bosses are here proportioned so that the distorted portions of the pad will engage the casing and bosses at approximately the same time, whereby these parts co-act to jointly limit the further distortion of the'pad and the relative displacement-of the sections. Also the lengths of 'the' bosses 43' and A l areso proportioned as to provide a space 47 between their confronting faces 13 and 49 which progressively closes during relative displacement of the sections, whereby these confronting faces are brought into abutment upon engagement of the core wall 42 of the pad with the bosses. As will be seen in Figure 3, this co-action provides a 1 remove mm th pain of contact of he d storted ad mater al wi h the a f i the e g-plies e the prese t s enties has bee and describ d i h eaneall is ne ried hand drill mate tapered grinding s ed! of. the trauma for grindiggg value 5 1 in which combination the coupling is particularly useful, other types f drives and rinder attachm nts may licens d- For mple, the s r a -iris ma use in any power grinding set-up either of stationary or Port b mounting, h as h han eld s te as shown, Or a flexible cable drive, or the e. The coupling is particularly adapted for use with almost any abrasive type grinder attachment and is well suited for use with sand paper or emery covered disks of either the flexible or rigid backing type. The coupling works very well with abrasive disks which are rigidly backed, due to the resilient flexibility provided by the coupling, and in such applications promotes increased efficiency while preventing danger of the disk digging into the surface being sanded or otherwise abrasively finished.

I claim:

1. A coupling of the character described comprising, a pair of sections mounted with opposite sides in confronting relation and concentric to a common axis, said sections having hub portions formed for securing to a drive shaft and a grinder attachment respectively and being formed with concentric cylindrical bosses extending in an axial direction from said faces, a pad of resiliently distortable material having opposite sides engaged with said faces and formed with a hollow core receiving concentrically therein said cylindrical bosses, means clamping said faces against said pad sides to place said pad under initial resilient compression and permitting relative rotational displacement of said sections, the inside Wall of said core being spaced by a predetermined clearance from said bosses, said pad being distortable at said core into said clearance to permit relative displacement of said sections, and said bosses functioning to engage said pad core wall to limit the distortion thereat and the extent of relative displacement of said sections.

2. A coupling of the character described comprising, a pad of resiliently distortable material having opposed substantially parallel sides and a hollow core defined by an internal substantially cylindrical wall, a pair of disk-shaped sections having opposed confronting faces mounted against said pad sides, said sections having hub portions formed for securing to a drive shaft and a grinder attachment respectively and being formed with concentric cylindrical bosses of equal diameter extending axially from said faces and into said core from the opposite sides thereof, means clamping said faces against said pad sides to place said pad under initial compression and permitting relative rotational displacement of said sections, said means providing a predetermined spacing between the confronting end portions of said bosses, the diameter of said core wall being greater by a predetermined clearance than the (amide am ter of said pad beins distortable at said core said clearance to peemit relative rotational displacement and axial approach of said sections, said tbosses v functioning to engage said pore rwalliandiio abut at said end portions delimit the distortion 20f said pad and the extent of relatixe displacement of said sections. i

3. In a co p ing of the character described, a pair sections formed with cos-axial means for securinga grind shaft and ;-a grinder attachment respectively, said faces being formed with con, fronting faces symmetrical to the common axis of (said means and having concentric cylindrical bosses extending inlan axial direction from said faces, an (annular pad of resiliently distortable material vhea ing onpositersides and a substane tially circular periphery and a concentri "hollow core, said pad :being mounted between said sectionsconcentricaliy to .said .axis with said zpad sides engaged i-bysaid faces and withathe pad wall defining ,said icore surrounding in spaced relation said cylindrical bosses Ito provide a :clearance therebetween, a casing having a substantially cylindrical internal wall surrounding said pad periphery in predetermined spaced relation thereto to provide clearance therebetween, said casing wall and said bosses cooperating with said faces to define an annular chamber containing said pad and having a volume exceeding the volume of said pad by the amount of said clearances, said pad being distortable at its periphery and at its core into said clearances to permit while resiliently resisting relative displacement of said sections, said wall and said bosses functioning to engage said pad periphery and core respectively to limit the distortion thereat and the extent of relative displacement of said sections.

4. In a coupling of the character described, a pair of sections formed with co-axial means for securing a grind shaft and a grinder attachment respectively, said faces being formed with confronting faces symmetrical to the common axis of said means and having concentric cylindrical bosses extending in an axial direction from said faces, an annular pad of resiliently distortable material having opposite sides and a substantially circular periphery and a concentric hollow core, said pad being mounted between said sections concentrically to said axis with said pad sides engaged by said faces and with the pad wall defining said core surrounding in spaced relation said cylindrical bosses to provide a clearance therebetween, a casing having a substantially cylindrical internal wall surrounding said pad periphery in concentrically spaced relation thereto to provide a clearance thereat, said bosses and said casing wall cooperating with said faces to define an annular chamber containing said pad and having a volume greater than the volume of said pad by the amount of said clearances, said pad being distortable at its periphery and at its core into said clearances to permit while resiliently resisting relative displacement of said sections, securing said casing to said sections and clamping said faces against said pad sides to place said pad under initial compression and. permitting relative displacement of said sections, said last named means providing a predetermined spacing between the confronting end portions of said bosses, said bosses and said casing wall functioning to engage said pad core wall and periphery respectively and said boss end portions functioning to abut to limit the distortion of said pad, and the extent of relative displacement of said sections. I

5. In a coupling of the character described, a generally cylindrical annular pad of resiliently distortable material having opposed substantially parallel sides and a hollow core defined by an internal substantially cylindrical wall, a pair of disk-shaped sections having opposed confronting faces abutting said pad sides, said sec tions having hub portions formed for securing to a drive shaft and a grinder attachment respectively and being formed'with concentric cylindrical bosses of equal diameter extending axially from said faces and into said pad core, a tubular casing mounted in encircling concentric relation about said pad and said sections and having an inturned flange at one end adapted to engage the outer side of one of said sections for securing said sections against withdrawal therefrom, the other end of said casing being formed in crimped engagement with the other of said sections for securing said casing thereto, with said pad clamped between said faces under a predetermined degree of initial compression, the inside and outside diameters of said pad being of dimensions providing annular clearances between said pad and said bosses and casing respectively, and means preventing slippage of said pad sides relative to their abutting section faces, said last named means cooperating with the resilience of said pad to distort said pad at its periphery and at its core into said clearances to permit while resiliently resisting relative displacement of said sections, said Wall and said bosses functioning to engage said pad periphery and core respectively to limit the distortion thereat and the extent of relative displacement of said sections.

a WILLIAM J. HIGERT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,366,502 Fitz Gerald Jan. 2, 1945 2,514,051 Gredell July 4, 1950 

